package _01_第一季._00_公共接口;

public interface Set<E> {
    int size();
    boolean isEmpty();
    void clear();
    boolean contains(E element);
    void add(E element);
    void remove(E element);

    void traversal(Visitor<E> visitor);

    public abstract class Visitor<E>{
        boolean stop;

       public abstract boolean visit(E element);
    }
}
